Based on water chemistry analysis, metagenomic techniques, and multivariate statistical analysis, this study systematically investigated the spatial distributions of nitrogen pollution, nitrogen metabolism genes, and bacterial communities, as well as their environmental drivers in Dianchi Lake. We found that the total dissolved nitrogen concentration in Caohai (4.09 mg/L) was significantly higher than that in Waihai (1.48 mg/L), with nitrate nitrogen (NO₃⁻-N) and dissolved organic nitrogen (DON) as the dominant forms, respectively. Nitrogen metabolism genes exhibited significant spatial heterogeneity, with higher relative abundances of dissimilatory nitrogen reduction and denitrification genes in Caohai, whereas genes related to assimilatory nitrogen reduction and ammonification were more dominant in Waihai. Nitrogen metabolism bacteria were mainly composed of Proteobacteria, Bacteroidota, and Cyanobacteria, with the toxin-producing cyanobacteria Planktothrix and Microcystis as the dominant genera. Mantel analysis and Spearman correlation analysis indicated that TDN, NO₃⁻-N, ammonium (NH₄⁺-N) and water temperature were the key environmental factors influencing nitrogen metabolism genes and bacteria. 

基于水化学分析、宏基因组技术及多元统计分析, 系统地研究滇池氮污染状况、氮代谢功能基因与氮代谢细菌的空间分布及其驱动因素。结果表明, 滇池草海的溶解性总氮浓度(4.09 mg/L)显著高于外海(1.48 mg/L), 分别以硝态氮和可溶性有机氮为主。氮代谢基因呈现显著的空间异质性, 草海中氮异化还原和反硝化基因的相对丰度较高, 而外海中氮同化还原和氨化作用相关基因占据优势。滇池水体中氮代谢细菌主要由变形菌门、拟杆菌门和蓝细菌门构成, 其中产毒蓝细菌Planktothrix和Microcystis是主要优势属。Mantel分析和Spearman相关性分析表明, 总氮、硝态氮、铵氮和水温是影响氮代谢基因及氮代谢细菌群落的关键环境因子。